Detection of process components in food process streams by fluorescence

Abstract

The invention is a method of monitoring for the presence of certain constituents of food processing streams by measurement of fluorescence. The constituent monitored can be a fluorescing impurity of a food product, or the food product itself if such naturally fluoresces. Moreover, losses of the constituent to be monitored may be determined by concurrent measurement of fluorescence of a fluorescent material added to the food process stream. The method is applicable to the following food processing streams among others: meat, vegetable oil, sugar beet, sugar cane, grain, poultry, fruit and soybean processing streams. Upon determination of a variation of the fluorescing constituent to be measured, the food process can be adjusted accordingly.

We claim: 
     
       1. A method for the monitoring of the variation in amount of fluorescing impurities during food processing in food process streams which contain fluorescing impurities comprising the steps of: A) adding a known amount of a substantially inert fluorescent material to said food process stream;   B) measuring the fluorescence emission wavelengths of the fluorescent impurity and the fluorescent material of step A over time utilizing a fluorometer;   C) calculating the ratio of the fluorescence of the fluorescent impurity to the fluorescence of the fluorescent material of step A;   D) determining from the change in the ratio of step C over time that a variation in the amount of the fluorescing impurity in the food process stream has occurred; and   E) adjusting the food process appropriately to compensate for the measured variation in the amount of the fluorescing impurity in said food process stream.   
     
     
       2. The method of claim 1 wherein the fluorescent material is selected from the group consisting of naphthalene sulfonate salt, mono- and dimethyl naphthalene sulfonate salt, 1,5 naphthalene disulfonate salt, 2-naphthalene sulfonate salt, riboflavin, tyrosine, beta carotene, 1-tryptophan, sodium lignosulfonate, sodium humate, fluorescene and 1-dopa. 
     
     
       3. The method of claim 2 wherein the food process stream is selected from the group consisting of meat, vegetable oil, sugar beet, sugar cane, grain, poultry, fruit and soybean processing streams. 
     
     
       4. The method of claim 2 wherein the food process stream is a sugar beet processing stream and the fluorescent material is mono- and dimethyl naphthalene sulfonate salt. 
     
     
       5. The method of claim 2 wherein the food process is selected from the group consisting of boiling, chilling, drying, purifying, crystallizing, extracting, pasteurizing, thermal processing, grinding, pH adjustment, softening, waste treatment and clarifying. 
     
     
       6. The method of claim 2 wherein the concentration of the fluorescent material added to the food process stream is from about 0.1 ppb to about 250 ppm. 
     
     
       7. The method of claim 2 wherein the concentration of the fluorescent material added to the food process stream is from about 0.5 ppb to about 100 ppm. 
     
     
       8. The method of claim 2 wherein the concentration of the fluorescent material added to the food process stream is from about 1 ppb to about 25 ppm. 
     
     
       9. The method of claim 2 wherein the measurement of the fluorescence is continuously monitored by a fluorometer. 
     
     
       10. A method for the determination of the presence of contaminating food process streams which contain fluorescent moieties in the circulating water of food processing equipment which contains circulating water comprising the steps of: A) adding a known amount of a substantially inert fluorescent material to said circulating waters;   B) measuring the fluorescence emission wavelengths of the fluorescent moiety and the fluorescent material of step A over time utilizing a fluorometer;   C) calculating the ratio of the fluorescence of the fluorescent moiety to the fluorescence of the fluorescent material of step A;   D) determining from the change in the ratio of step C over time that a contamination of the circulating water of the food processing equipment has occurred; and   E) adjusting the food process appropriately to avoid further contamination of said food processing equipment.   
     
     
       11. The method of claim 10 wherein the fluorescent material is selected from the group consisting of naphthalene sulfonate salt, mono- and dimethyl naphthalene sulfonate salt, 1,5 naphthalene disulfonate salt, 2-naphthalene sulfonate salt, riboflavin, tyrosine, beta carotene, 1-tryptophan, sodium lignosulfonate, sodium humate, fluorescene and 1-dopa. 
     
     
       12. The method of claim 11 wherein the food process stream is selected from the group consisting of meat, vegetable oil, sugar beet, sugar cane, grain, poultry, fruit and soybean processing streams. 
     
     
       13. The method of claim 11 wherein the food process stream is a sugar beet processing stream and the fluorescent material is mono- and dimethyl naphthalene sulfonate salt. 
     
     
       14. The method of claim 11 wherein the food processing equipment which contains circulating water is selected from the group consisting of boilers, chillers, evaporators, pasteurizers, and thermal processors. 
     
     
       15. The method of claim 11 wherein the concentration of the fluorescent material added to the food process stream is from about 0.1 ppb to about 250 ppm. 
     
     
       16. The method of claim 11 wherein the concentration of the fluorescent material added to the food process stream is from about 0.5 ppb to about 100 ppm. 
     
     
       17. The method of claim 11 wherein the concentration of the fluorescent material added to the food process stream is from about 1 ppb to about 25 ppm. 
     
     
       18. The method of claim 11 wherein the measurement of the fluorescence is continuously monitored by a fluorometer. 
     
     
       19. A method for quantifying the amount of a food substance present in a food processing stream wherein the food substance is present in a known ratio to a fluorescing moiety in the food processing stream comprising the steps of: A) adding a known amount of a substantially inert fluorescent material to said food process stream;   B) measuring the fluorescence emission wavelengths of the fluorescing moiety and the fluorescent material of step A over time utilizing a fluorometer;   C) calculating the ratio of the fluorescence of the fluorescent moiety to the fluorescence of the fluorescent material of step A; and   D) determining from the change in the ratio of step C over time that a proportional variation in the amount of the food substance in said food processing stream has occurred.   
     
     
       20. The method of claim 19 wherein the fluorescent material is selected from the group consisting of naphthalene sulfonate salt, mono- and dimethyl naphthalene sulfonate salt, 1,5 naphthalene disulfonate salt, 2-naphthalene sulfonate salt, riboflavin, tyrosine, beta carotene, 1-tryptophan, sodium lignosulfonate, sodium humate, fluorescene and 1-dopa. 
     
     
       21. The method of claim 20 wherein the food processing stream is selected from the group consisting of meat, vegetable oil, sugar beet, sugar cane, grain, poultry, fruit and soybean processing streams. 
     
     
       22. The method of claim 20 wherein the food substance is selected from the group consisting of meat, poultry, beet sugar, sugar cane, grain, soybeans, fruit and vegetable oil. 
     
     
       23. The method of claim 20 wherein the food processing stream is a sugar beet processing stream and the fluorescent material is mono- and dimethyl naphthalene sulfonate salt. 
     
     
       24. The method of claim 20 wherein the fluorescing moiety is selected from the group consisting of: DC Red 22, DC Green 8, FDC Red 2, DC Yellow 10, DC Green 5, FDC Blue 1, FDC Blue 2, FDC Yellow 5 and FDC Yellow 6. 
     
     
       25. The method of claim 20 wherein the concentration of the fluorescent material added to the food process stream is from about 0.1 ppb to about 250 ppm. 
     
     
       26. The method of claim 20 wherein the concentration of the fluorescent material added to the food process stream is from about 0.5 ppb to about 100 ppm. 
     
     
       27. The method of claim 20 wherein the concentration of the fluorescent material added to the food process stream is from about 1 ppb to about 25 ppm. 
     
     
       28. The method of claim 20 wherein the measurement of the fluorescence is continuously monitored by a fluorometer. 
     
     
       29. The method of claim 20 wherein the food process is adjusted appropriately to compensate for the variation in the amount of the food substance in said food processing stream.